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Titolo: Structure and [2+2] cycloreversion of the cyclobutane radical cation
Autore: Wiest, O;
 Indirizzi:
 Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA Univ Notre Dame Notre Dame IN USA 46556 Biochem, Notre Dame, IN 46556 USA
 Titolo Testata:
 JOURNAL OF PHYSICAL CHEMISTRY A
fascicolo: 39,
volume: 103,
anno: 1999,
pagine: 7907  7911
 SICI:
 10895639(19990930)103:39<7907:SA[COT>2.0.ZU;24
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 POTENTIALENERGY SURFACE; DENSITYFUNCTIONAL CALCULATIONS; RINGOPENING REACTION; ABINITIO; DNA PHOTOLYASE; REARRANGEMENT; ISOMERIZATION; QUADRICYCLANE; DECOMPOSITION; DIMERIZATION;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Physical, Chemical & Earth Sciences
 Citazioni:
 60
 Recensione:
 Indirizzi per estratti:
 Indirizzo: Wiest, O Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA Univ Notre Dame Notre Dame IN USA 46556 Notre Dame, IN 46556 USA



 Citazione:
 O. Wiest, "Structure and [2+2] cycloreversion of the cyclobutane radical cation", J PHYS CH A, 103(39), 1999, pp. 79077911
Abstract
The [2+2] cycloreversion reaction of the cyclobutane radical cation was studied using highlevel MO and DFT methods. Three distinct, but energetically very similar, structures are located for the cyclobutane radical cation: a parallelogram that corresponds to the minimum on the JahnTeller surface,a rhombus, corresponding to a transition structure connecting two parallelograms, and a rectangle that is a secondorder saddle point. Intrinsic reaction coordinate calculations show that the reaction proceeds in a concertedfashion. The calculated reaction mode is not consistent with a putative acyclic intermediate, but rather shifts the two ethylene fragments relative to each other. The transition structure connects the product complex to the parallelogram structure of the cyclobutane radical cation. The overall thermochemistry calculated by the QCISD(T)//QCISD and the B3LYP methods are in good agreement with the available experimental data. It is shown that the experimental hyperfine coupling constants do not imply a puckered structure,as claimed earlier. The electronic structure and magnetic properties of the transition structure are elucidated by NICS calculations.
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Documento generato il 26/11/20 alle ore 19:04:14